What part of physical strength do you not under stand?
Let me put it this way, which one is S.T.R.O.N.G.E.R.?
Strength: The magnitude of physical strength, often referred to as the ability of a person or animal to exert force on physical objects using muscles.
Not which one could win in a fight, but which one has more "strength"
My opinion is that aliens don't feel pain, or comfort, which allows them to use as much force as they please, without straining themselves. Their muscles are wires that are powered by their molecular acid, so the muscles won't get tired. They can use as much force as they want. A down side is that their muscles can't grow.
A predator's muscle develops like a gorilla's would, so the average teen would have 300 pounds of muscle, and an adult would have 400 pounds of muscle. So the preds can push/press about 200 pounds, but they can hurt themselves if they lift things that are to heavy.
Therefore, an alien can push/press more.
So aliens are physically stronger, than preds.